Input Panels > IPR Types > Gas IPR Options:

Gas IPR Options

Quadratic Flow Equation: The IPR is generated using the quadratic flow equation which accounts for turbulence effects. The calculations are carried in terms of real gas pseudo pressure to account for variations in viscosity and compressibility (Z) factor with pressure.

Multipoint Flow Test: The IPR is generated using the back pressure equation and test data to generate current and predicted reservoir performance.

Back Pressure C and N: The IPR is generated using input values for the back pressure equation. In some areas, these values are fixed by regulatory bodies and this provides an option to lock in on a specific value.

Babu & Odeh Horizontal Well Model: This IPR model uses the method outlined by Babu and Odeh to model Horizontal well performance which includes the effects of position in the drainage area. Several simpler models are available but this one supersedes the capabilities of each of those.

Fractured Well Model: This IPR uses either the linear flow equation for very early time predictions or the quadratic equation with a modified rw for pseudo-radial flow during late times (tdxf > 0.016). Please refer to SPE monograph 12 RECENT ADVANCES IN HYDRAULIC FRACTURING pages 325-331 for a detailed discussion of the method. This is a transient model and is therefore dependent on time.

Gas Deliverability with Non-Darcy Skin Factor: This method is relevant in high rate and/or low pressure (high velocity) gas completions where sufficient irreversible pressure drop occurs near the wellbore that it materially affects the IPR curve, causing it to bend downward at higher rates. One formulation of this behavior includes total skin as a combination of Mechanical and “non-mechanical” or non-Darcy skin which is expressed as D*q where the units of D are 1/ the units of q. Typical values are 0.00007 /mscfpd. (See Lee & Wattenbarger’s Gas Reservoir Engineering P.117).

User Defined IPR Model: This IPR model allows entry of user input IPR parameters in case none of the above models adequately describes the well behavior.